In prior art, heat pumps are employed in heating systems for heating interior spaces in buildings. In order to maximize the efficiency of the heat pump, or specifically the so-called coefficient of performance (COP), a heating system should be chosen which requires only a low final water temperature, since the hotter the water delivered by the heat pump, the lower the COP will be. Thus, usually heat pumps are set so as to supply water as cold as possible while nevertheless providing the necessary heating energy in order to provide the desired room temperature in the area heated by the heating system.
However, the heating demand for heating interior spaces or rooms in a building changes with changing weather conditions. Thus, also the set-point for the water temperature needs to be changed accordingly depending on the outside temperature whereby the setpoint for the water temperature is determined by the heat curve on the basis of the outside temperature. Thus, in a normal control structure of a heat pump for e.g., a family house is such that the outside temperature Tout is mapped to a setpoint for the water temperature Tw,ref by the heat curve, and the compressor is adjusted such that the water temperature reaches the setpoint and a specific room temperature Tn is achieved. As the shape of the heat curve, however, depends on factors such as the heating system and insulation, the user has to manually adjust the heat curve to each system in order to achieve the desired room temperature.
In order to provide feedback of the room temperature, it is known in prior art to employ a single temperature sensor. The temperature sensor provides feedback of the room temperature at a distinct single location in the house or room, respectively, which feedback is used to adjust the water temperature setpoint. This increases the comfort in the area surrounding the location of the temperature sensor and provides the ability to compensate for temperature changes.
However, this approach has the drawback that it only provides feedback with respect to a single location. If the temperature nearby the sensor rises due to free heat, the compensation in the water temperature can result in water which is too cold for heating areas with less free heat than at the location where the temperature sensor is arranged.